U.S. patent number 9,997,718 [Application Number 15/008,076] was granted by the patent office on 2018-06-12 for organic photoelectric device image sensor and electronic device.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. The grantee listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Yong Wan Jin, Gae Hwang Lee, Kwang Hee Lee, Dong-Seok Leem, Sakurai Rie, Bulliard Xavier, Tadao Yagi, Sung Young Yun.
United States Patent |
9,997,718 |
Rie , et al. |
June 12, 2018 |
Organic photoelectric device image sensor and electronic device
Abstract
An organic photoelectric device includes a first electrode and a
second electrode facing each other, and an active layer between the
first electrode and the second electrode, the active layer
including an n-type semiconductor compound represented by Chemical
Formula 1 and a p-type semiconductor compound having selective
light absorption in a green wavelength region of about 500 nm to
about 600 nm.
Inventors: |
Rie; Sakurai (Suwon-si,
KR), Jin; Yong Wan (Seoul, KR), Yun; Sung
Young (Suwon-si, KR), Lee; Gae Hwang
(Seongnam-si, KR), Lee; Kwang Hee (Yongin-si,
KR), Leem; Dong-Seok (Hwaseong-si, KR),
Xavier; Bulliard (Seongnam-si, KR), Yagi; Tadao
(Hwaseong-si, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si, Gyeonggi-do |
N/A |
KR |
|
|
Assignee: |
Samsung Electronics Co., Ltd.
(Gyeonggi-do, KR)
|
Family
ID: |
57112371 |
Appl.
No.: |
15/008,076 |
Filed: |
January 27, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160301013 A1 |
Oct 13, 2016 |
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Foreign Application Priority Data
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Apr 13, 2015 [KR] |
|
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10-2015-0052019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07D
495/22 (20130101); C09K 11/06 (20130101); H01L
27/307 (20130101); H05B 33/14 (20130101); H01L
51/0053 (20130101); H01L 51/0051 (20130101); H01L
51/0071 (20130101); H01L 51/4253 (20130101); H01L
51/0061 (20130101); H01L 51/006 (20130101); H01L
2251/308 (20130101); H01L 51/0078 (20130101) |
Current International
Class: |
C07D
495/22 (20060101); H01L 51/00 (20060101); C09K
11/06 (20060101); H05B 33/14 (20060101); H01L
27/30 (20060101); H01L 51/50 (20060101); H01L
51/42 (20060101) |
Field of
Search: |
;546/41 ;548/405
;313/504 ;257/40,E51.05 ;428/917 |
References Cited
[Referenced By]
U.S. Patent Documents
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101693719 |
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CN |
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101885732 |
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Nov 2010 |
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CN |
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102344456 |
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Feb 2012 |
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CN |
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102351879 |
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Feb 2012 |
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CN |
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103399072 |
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Nov 2013 |
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CN |
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103408570 |
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Nov 2013 |
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CN |
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WO 9424612 |
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WO |
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Feb 2014 |
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WO |
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|
Primary Examiner: Balasubramanian; Venkataraman
Attorney, Agent or Firm: Harness, Dickey & Pierce,
P.L.C.
Claims
What is claimed is:
1. An organic photoelectric device comprising: a first electrode
and a second electrode facing each other; and an active layer
between the first electrode and the second electrode, the active
layer including an n-type semiconductor compound represented by
Chemical Formula 1 and a p-type semiconductor compound having
selective light absorption in a green wavelength region of about
500 nm to about 600 nm: ##STR00023## wherein, in Chemical Formula
1, each of R.sup.1 and R.sup.2 are independently one of a
substituted or unsubstituted C.sub.1 to C.sub.6 linear or branched
alkyl group, a substituted or unsubstituted phenyl group, a
substituted or unsubstituted 5-membered to 6-membered heteroaryl
group, a substituted or unsubstituted C.sub.3 to C.sub.6 cycloalkyl
group, or a substituted or unsubstituted 3-membered to 6-membered
heterocycloalkyl group, wherein at least one of R.sup.1 and R.sup.2
is a substituted or unsubstituted phenyl group, a substituted or
unsubstituted 5-membered to 6-membered heteroaryl group, a
substituted or unsubstituted C.sub.3 to C.sub.6 cycloalkyl group,
or a substituted or unsubstituted 3-membered to 6-membered
heterocycloalkyl group, and each of Cy1 and Cy2 are independently
selected from Chemical Formulae 2-1, 2-2, and 2-5: ##STR00024##
wherein, in Chemical Formula 2-1, R.sup.11 is hydrogen, a cyano
group (--CN), a carboxyl group (--COOH), an ester group (--COOR,
wherein R is a C.sub.1 to C.sub.6 linear or branched alkyl group),
a phenyl group, or a phenyl group substituted with a C.sub.1 to
C.sub.6 alkyl group, wherein, in Chemical Formula 2-2, Y is O, S,
or NR (wherein R is hydrogen, cyano group, or a C.sub.1 to C.sub.6
linear or branched alkyl group), and wherein, in Chemical Formula
2-5, R.sup.12 is hydrogen, a cyano group, a carboxyl group, or an
ester group (--COOR, wherein R is a C.sub.1 to C.sub.6 linear or
branched alkyl group), and m is an integer of 0 to 1.
2. The organic photoelectric device of claim 1, wherein in Chemical
Formula 1, Cy1 and Cy2 are the same or different.
3. The organic photoelectric device of claim 1, wherein the n-type
semiconductor compound represented by Chemical Formula 1 has 7 to
10 rings.
4. The organic photoelectric device of claim 1, wherein each of the
R.sup.1 and R.sup.2 are independently a C.sub.1 to C.sub.6 linear
or branched alkyl group substituted with cyano group or a halide
group, a phenyl group substituted with a cyano group or a halide
group, a 5-membered to 6-membered heteroaryl group substituted with
a cyano group or a halide group, a C.sub.3 to C.sub.6 cycloalkyl
group substituted with a cyano group or a halide group, or a
3-membered to 6-membered heterocycloalkyl group substituted with a
cyano group or a halide group.
5. The organic photoelectric device of claim 1, wherein the p-type
semiconductor compound is a compound represented by Chemical
Formula 3: ##STR00025## wherein, in Chemical Formula 3, R.sup.21 to
R.sup.23 are independently hydrogen, a substituted or unsubstituted
C.sub.1 to C.sub.30 alkyl group, a substituted or unsubstituted
C.sub.6 to C.sub.30 aryl group, a substituted or unsubstituted
C.sub.3 to C.sub.30 heteroaryl group, a halide group, a
halogen-containing group, or a combination thereof, each of a, b,
and c are independently an integer ranging from 1 to 3, and X is a
halide group.
6. The organic photoelectric device of claim 5, wherein in Chemical
Formula 3, R.sup.21 to R.sup.23 are independently a substituted or
unsubstituted C.sub.1 to C.sub.30 alkyl group, a substituted or
unsubstituted C.sub.6 to C.sub.30 aryl group, or a substituted or
unsubstituted C.sub.3 to C.sub.30 heteroaryl group.
7. The organic photoelectric device of claim 1, wherein the p-type
semiconductor compound is a compound represented by Chemical
Formula 4: ##STR00026## wherein, in Chemical Formula 4, Z is Se,
Te, S(.dbd.O), S(.dbd.O).sub.2, or SiR.sup.aR.sup.b (wherein
R.sup.a and R.sup.b are independently hydrogen or a C.sub.1 to
C.sub.10 alkyl group), each of Ar.sup.1 and Ar.sup.2 are
independently one of a substituted or unsubstituted C.sub.6 to
C.sub.30 aryl group or a substituted or unsubstituted C.sub.4 to
C.sub.30 heteroaryl group, each of R.sup.31 to R.sup.36 are
independently hydrogen, a substituted or unsubstituted C.sub.1 to
C.sub.30 alkyl group, a substituted or unsubstituted C.sub.6 to
C.sub.30 aryl group, a substituted or unsubstituted C.sub.4 to
C.sub.30 heteroaryl group, or a halide and cyano group, m is an
integer ranging from 0 to 4, and n is 0 or 1.
8. The organic photoelectric device of claim 7, wherein the
compound represented by Chemical Formula 4 has 5 to 7 aromatic
rings.
9. The organic photoelectric device of claim 7, wherein the
Ar.sup.1 and Ar.sup.2 are a substituted or unsubstituted C.sub.6 to
C.sub.20 aryl group.
10. The organic photoelectric device of claim 7, wherein at least
one of the Ar.sup.1 and Ar.sup.2 is a naphthyl group or an
anthracenyl group.
11. The organic photoelectric device of claim 1, wherein the active
layer has a maximum absorption wavelength (.lamda..sub.max) of
about 500 nm to about 600 nm.
12. The organic photoelectric device of claim 1, wherein the active
layer shows a light absorption curve having a full width at half
maximum (FWHM) of about 50 nm to about 140 nm.
13. The organic photoelectric device of claim 1, wherein the active
layer comprises an intrinsic layer including the n-type
semiconductor compound and the p-type semiconductor compound.
14. The organic photoelectric device of claim 13, wherein the
active layer further comprises at least one of a p-type layer on
one side of the intrinsic layer and an n-type layer on an other
side of the intrinsic layer.
15. An image sensor comprising the organic photoelectric device of
claim 1.
16. The image sensor of claim 15, further comprising: a
semiconductor substrate integrated with a plurality of first
photo-sensing devices configured to sense light in a blue
wavelength region and a plurality of second photo-sensing devices
configured to sense light in a red wavelength region, wherein the
organic photoelectric device is on the semiconductor substrate and
selectively absorbs light in a green wavelength region.
17. The image sensor of claim 16, wherein the plurality of first
photo-sensing devices and the plurality of second photo-sensing
devices are stacked in a vertical direction on the semiconductor
substrate.
18. The image sensor of claim 16, further comprising: a color
filter layer between the semiconductor substrate and the organic
photoelectric device, the color filter layer including a blue
filter configured to selectively absorb light in a blue wavelength
region and a red filter configured to selectively absorb light in a
red wavelength region.
19. The image sensor of claim 15, wherein the organic photoelectric
device is a green photoelectric device, and the green photoelectric
device, a blue photoelectric device configured to selectively
absorb light in a blue wavelength region, and a red photoelectric
device configured to selectively absorb light in a red wavelength
region are stacked.
20. An electronic device comprising the image sensor of claim
15.
21. An organic photoelectric device comprising: a first electrode
and a second electrode facing each other and an active layer
between the first electrode and the second electrode, the active
layer including an n-type semiconductor compound represented by
Chemical Formula 1 and a p-type semiconductor compound having
selective light absorption in a green wavelength region of about
500 nm to about 600 nm: ##STR00027## wherein, in Chemical Formula
1, each of R.sup.1 and R.sup.2 are independently a substituted or
unsubstituted phenyl group, a substituted or unsubstituted
5-membered to 6-membered heteroaryl group, a substituted or
unsubstituted C.sub.3 to C.sub.6 cycloalkyl group, or a substituted
or unsubstituted 3-membered to 6-membered heterocycloalkyl group,
and each of Cy1 and Cy2 are independently selected from Chemical
Formulae 2-1, 2-2, and 2-5: ##STR00028## wherein, in Chemical
Formula 2-1, R.sup.11 is hydrogen, cyano group, a carboxyl group,
an ester group (--COOR, wherein R is a C.sub.1 to C.sub.6 linear or
branched alkyl group), a phenyl group, or a phenyl group
substituted with a C.sub.1 to C.sub.6 alkyl group, wherein, in
Chemical Formula 2-2, Y is O, S, or NR (wherein R is hydrogen,
cyano group, or a C.sub.1 to C.sub.6 linear or branched alkyl
group), and wherein, in Chemical Formula 2-5, R.sup.12 is hydrogen,
a cyano group, a carboxyl group, or an ester group (--COOR, wherein
R is a C.sub.1 to C.sub.6 linear or branched alkyl group), and m is
an integer of 0 to 1, and wherein at least one of Cy1 and Cy2 is
Chemical Formula 2-1.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit of Korean
Patent Application No. 10-2015-0052019 filed in the Korean
Intellectual Property Office on Apr. 13, 2015, the entire contents
of which are incorporated herein by reference.
BACKGROUND
1. Field
Example embodiments relate to an organic photoelectric device, an
image sensor, and an electronic device.
2. Description of the Related Art
A photoelectric device converts light into an electrical signal
using photoelectric effects, and may include a photodiode and/or a
phototransistor. The photoelectric device may be applied to an
image sensor, a solar cell and/or an organic light emitting
diode.
An image sensor including a photodiode requires relatively high
resolution and thus a relatively small pixel. At present, a silicon
photodiode is widely used, but may have a problem of deteriorated
sensitivity since the silicon photodiode has a relatively small
absorption area due to relatively small pixels. Accordingly, an
organic material that is capable of replacing silicon has been
researched.
The organic material has a relatively high extinction coefficient
and selectively absorbs light in a particular wavelength region
depending on a molecular structure, and thus may simultaneously
replace a photodiode and a color filter and resultantly improve
sensitivity and contribute to relatively high integration.
SUMMARY
Example embodiments provide an organic photoelectric device being
capable of selectively absorbing light in a green wavelength region
and improving efficiency.
Example embodiments also provide an image sensor including the
organic photoelectric device and an electronic device.
According to example embodiments, an organic photoelectric device
includes a first electrode and a second electrode facing each
other, and an active layer between the first electrode and the
second electrode, the active layer including an n-type
semiconductor compound represented by Chemical Formula 1 and a
p-type semiconductor compound having selective light absorption in
a green wavelength region of about 500 nm to about 600 nm.
##STR00001##
In Chemical Formula 1,
each of R.sup.1 and R.sup.2 are independently one of a substituted
or unsubstituted C.sub.1 to C.sub.6 linear or branched alkyl group,
a substituted or unsubstituted phenyl group, a substituted or
unsubstituted 4-membered to 6-membered heteroaryl group, a
substituted or unsubstituted C.sub.3 to C.sub.6 cycloalkyl group,
and a substituted or unsubstituted 3-membered to 6-membered
heterocycloalkyl group, and
each of Cy1 and Cy2 are independently selected from Chemical
Formulae 2-1 to 2-5.
##STR00002##
In Chemical Formula 2-1,
R.sup.11 is one of hydrogen, a cyano group (CN), a carboxyl group
(--COOH), an ester group (--COOR, wherein R is a C.sub.1 to C.sub.6
linear or branched alkyl group), a phenyl group, and a phenyl group
substituted with a C.sub.1 to C.sub.6 alkyl group,
in Chemical Formula 2-2,
Y is one of O, S, and NR (wherein R is one of hydrogen, a cyano
group (CN), and a C.sub.1 to C.sub.6 linear or branched alkyl
group), and
in Chemical Formula 2-5,
R.sup.12 is one of hydrogen, a cyano group (CN), a carboxyl group
(--COOH), and an ester group (--COOR, wherein R is a C.sub.1 to
C.sub.6 linear or branched alkyl group), and
m is an integer of 0 to 1.
In Chemical Formula 1, Cy1 and Cy2 may be the same or
different.
The n-type semiconductor compound represented by Chemical Formula 1
may have 6 to 10 rings.
Each of the R.sup.1 and R.sup.2 may independently be one of a
C.sub.1 to C.sub.6 linear or branched alkyl group substituted with
an electron withdrawing group, a phenyl group substituted with an
electron withdrawing group, a 4-membered to 6-membered heteroaryl
group substituted with an electron withdrawing group, a C.sub.3 to
C.sub.6 cycloalkyl group substituted with an electron withdrawing
group, and a 3-membered to 6-membered heterocycloalkyl group
substituted with an electron withdrawing group. Herein, the
electron withdrawing group may be a cyano group or a halide
group.
The p-type semiconductor compound may be a compound represented by
Chemical Formula 3.
##STR00003##
In Chemical Formula 3,
each of R.sup.21 to R.sup.23 are independently one of hydrogen, a
substituted or unsubstituted C.sub.1 to C.sub.30 alkyl group, a
substituted or unsubstituted C.sub.6 to C.sub.30 aryl group, a
substituted or unsubstituted C.sub.3 to C.sub.30 heteroaryl group,
a halide group, a halogen-containing group, and a combination
thereof,
each of a, b, and c are independently an integer ranging from 1 to
3, and
X is one of a halide group, for example --F or --Cl, and
--Si(R.sup.a)(R.sup.b)(R.sup.c),
wherein each of the R.sup.a, R.sup.b, and R.sup.c are independently
one of a substituted or unsubstituted C.sub.1 to C.sub.30 alkyl
group, a substituted or unsubstituted C.sub.6 to C.sub.30 aryl
group, a substituted or unsubstituted C.sub.3 to C.sub.30
heterocyclic group, a substituted or unsubstituted C.sub.1 to
C.sub.30 alkoxy group, a substituted or unsubstituted amine group,
a substituted or unsubstituted C.sub.6 to C.sub.30 arylamine group,
a substituted or unsubstituted silyl group, and a combination
thereof.
In Chemical Formula 3, R.sup.21 to R.sup.23 may be an electron
donating functional group including one of a substituted or
unsubstituted C.sub.1 to C.sub.30 alkyl group, a substituted or
unsubstituted C.sub.6 to C.sub.30 aryl group, and a substituted or
unsubstituted C.sub.3 to C.sub.30 heteroaryl group.
The p-type semiconductor compound may be a compound represented by
Chemical Formula 4.
##STR00004##
In Chemical Formula 4,
Z is one of Se, Te, S(.dbd.O), S(.dbd.O).sub.2, and
SiR.sup.aR.sup.b (wherein R.sup.a and R.sup.b are one of hydrogen
and a C.sub.1 to C.sub.10 alkyl group),
each of Ar.sup.1 and Ar.sup.2 are one of a substituted or
unsubstituted C.sub.6 to C.sub.30 aryl group and a substituted or
unsubstituted C.sub.4 to C.sub.30 heteroaryl group,
each of R.sup.31 to R.sup.36 are independently one of hydrogen, a
substituted or unsubstituted C.sub.1 to C.sub.30 alkyl group, a
substituted or unsubstituted C.sub.6 to C.sub.30 aryl group, a
substituted or unsubstituted C.sub.4 to C.sub.30 heteroaryl group,
a halide, and a cyano group (CN),
m is an integer ranging from 0 to 4, and
n is 0 or 1.
The compound represented by Chemical Formula 4 may have 5 to 7
aromatic rings.
Ar.sup.1 and Ar.sup.2 may be a substituted or unsubstituted C.sub.6
to C.sub.20 aryl group.
At least one of the Ar.sup.1 and Ar.sup.2 may be one of a naphthyl
group and an anthracenyl group.
The active layer of the organic photoelectric device may have a
maximum absorption wavelength (.lamda..sub.max) of about 500 nm to
about 600 nm.
The active layer of the organic photoelectric device may show a
light absorption curve having a full width at half maximum (FWHM)
of about 50 nm to about 140 nm.
The active layer may include an intrinsic layer including the
n-type semiconductor compound and the p-type semiconductor
compound.
The active layer may further include at least one of a p-type layer
on one side of the intrinsic layer and an n-type layer on the other
side of the intrinsic layer.
Example embodiments provide an image sensor including the organic
photoelectric device.
The image sensor may include a semiconductor substrate integrated
with a plurality of first photo-sensing devices configured to sense
light in a blue wavelength region and a plurality of second
photo-sensing devices configured to sense light in a red wavelength
region, wherein the organic photoelectric device is on the
semiconductor substrate and configured to selectively absorb light
in a green wavelength region.
The plurality of first photo-sensing devices and the plurality of
second photo-sensing devices may be stacked in a vertical direction
on the semiconductor substrate.
The image sensor may further include a color filter layer between
the semiconductor substrate and the organic photoelectric device,
and the color filter layer including a blue filter configured to
selectively absorb light in a blue wavelength region and a red
filter configured to selectively absorb light in a red wavelength
region.
The organic photoelectric device may be a green photoelectric
device, and the green photoelectric device, a blue photoelectric
device configured to selectively absorb light in a blue wavelength
region, and a red photoelectric device configured to selectively
absorb light in a red wavelength region may be stacked.
Example embodiments also provide an electronic device including the
image sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view showing an organic photoelectric
device according to example embodiments,
FIG. 2 is a cross-sectional view showing an organic photoelectric
device according to example embodiments,
FIG. 3 is a schematic view showing an organic CMOS image sensor
according to example embodiments,
FIG. 4 is a cross-sectional view showing the organic CMOS image
sensor of FIG. 3,
FIG. 5 is a schematic cross-sectional view showing an organic CMOS
image sensor according to example embodiments,
FIG. 6 is a schematic cross-sectional view showing the organic CMOS
image sensor according to example embodiments,
FIG. 7 is a schematic view showing an organic CMOS image sensor
according to example embodiments, and
FIG. 8 is a graph showing external quantum efficiency (EQE)
depending on a wavelength of the organic photoelectric device
according to Example 1.
DETAILED DESCRIPTION
Example embodiments of the present inventive concepts will
hereinafter be described in detail, and may be more easily
performed by those who have common knowledge in the related art.
However, this disclosure may be embodied in many different forms
and is not construed as limited to the example embodiments set
forth herein.
In the drawings, the thickness of layers, films, panels, regions,
etc., are exaggerated for clarity. Like reference numerals
designate like elements throughout the specification. It will be
understood that when an element such as a layer, film, region, or
substrate is referred to as being "on" another element, it can be
directly on the other element or intervening elements may also be
present. In contrast, when an element is referred to as being
"directly on" another element, there are no intervening elements
present.
In the drawings, parts having no relationship with the description
are omitted for clarity of the embodiments, and the same or similar
constituent elements are indicated by the same reference numerals
throughout the specification.
It should be understood that, although the terms first, second,
third, etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers, and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer, or section from another region,
layer, or section. Thus, a first element, component, region, layer,
or section discussed below could be termed a second element,
component, region, layer, or section without departing from the
teachings of example embodiments.
Spatially relative terms (e.g., "beneath," "below," "lower,"
"above," "upper," and the like) may be used herein for ease of
description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
should be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
term "below" may encompass both an orientation of above and below.
The device may be otherwise oriented (rotated 90 degrees or at
other orientations) and the spatially relative descriptors used
herein interpreted accordingly.
The terminology used herein is for the purpose of describing
various embodiments only and is not intended to be limiting of
example embodiments. As used herein, the singular forms "a," "an,"
and "the" are intended to include the plural forms as well, unless
the context clearly indicates otherwise. It will be further
understood that the terms "includes," "including," "comprises,"
and/or "comprising," when used in this specification, specify the
presence of stated features, integers, steps, operations, elements,
and/or components, but do not preclude the presence or addition of
one or more other features, integers, steps, operations, elements,
components, and/or groups thereof.
Example embodiments are described herein with reference to
cross-sectional illustrations that are schematic illustrations of
idealized embodiments (and intermediate structures) of example
embodiments. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, example embodiments
should not be construed as limited to the shapes of regions
illustrated herein but are to include deviations in shapes that
result, for example, from manufacturing.
Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments belong. It will be further understood that terms,
including those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
As used herein, when specific definition is not otherwise provided,
the term "substituted" refers to one substituted with a substituent
selected from a halide group (--F, --Br, --Cl, or --I), a hydroxy
group, a nitro group, a cyano group, an amino group (--NRR',
wherein R and R' are a C.sub.1 to C.sub.6 linear or branched alkyl
group, an ester group (--COOR, wherein R is a C.sub.1 to C.sub.6
linear or branched alkyl group), a C.sub.1 to C.sub.10 alkyl group,
a C.sub.2 to C.sub.10 alkenyl group, a C.sub.2 to C.sub.10 alkynyl
group, a C.sub.1 to C.sub.10 alkoxy group, and a combination
thereof, instead of hydrogen of a compound or a functional
group.
As used herein, when specific definition is not otherwise provided,
the term "hetero" refers to one including 1 to 3 heteroatoms
selected from N, O, S, and P.
As used herein, when a definition is not otherwise provided, the
"halide group" refers to --F, --Cl, --Br, or --I, and the
"halogen-containing group" refers to a group where at least one
hydrogen is replaced by --F, --Cl, --Br, or --I. For example, the
haloalkyl group refers to an alkyl group where at least one
hydrogen is replaced by --F, --Cl, --Br, or --I. Examples of the
haloalkyl group may be a fluoroalkyl group, for example a
perfluoroalkyl group.
Hereinafter, an organic photoelectric device according to example
embodiments is described referring to drawings.
FIG. 1 is a cross-sectional view showing an organic photoelectric
device according to example embodiments.
Referring to FIG. 1, an organic photoelectric according to example
embodiments includes a first electrode 10 and a second electrode
20, and an active layer 30 interposed between the first electrode
10 and the second electrode 20.
One of the first electrode 10 and the second electrode 20 is an
anode and the other is a cathode. At least one of the first
electrode 10 and the second electrode 20 may be a
light-transmitting electrode, and the light-transmitting electrode
may be made of, for example, a transparent conductor (e.g., indium
tin oxide (ITO) or indium zinc oxide (IZO)), or a metal thin layer
of a monolayer or multilayer. When one of the first electrode 10
and the second electrode 20 is a non-light-transmitting electrode,
it may be made of, for example, an opaque conductor (e.g., aluminum
(Al)).
The active layer 30 includes a p-type semiconductor and an n-type
semiconductor to form a pn junction, and absorbs external light to
generate excitons and then separates the generated excitons into
holes and electrons.
The active layer 30 includes an n-type semiconductor compound
represented by Chemical Formula 1 and a p-type semiconductor
compound having selective light absorption in a green wavelength
region of about 500 nm to about 600 nm.
##STR00005##
In Chemical Formula 1,
each of R.sup.1 and R.sup.2 are independently one of a substituted
or unsubstituted C.sub.1 to C.sub.6 linear or branched alkyl group,
a substituted or unsubstituted phenyl group, a substituted or
unsubstituted 4-membered to 6-membered heteroaryl group, a
substituted or unsubstituted C.sub.3 to C.sub.6 cycloalkyl group,
and a substituted or unsubstituted 3-membered to 6-membered
heterocycloalkyl group, and
each of Cy1 and Cy2 are independently one of Chemical Formulae 2-1
to 2-5.
##STR00006##
In Chemical Formula 2-1,
R.sup.11 is one of hydrogen, a cyano group (CN), a carboxyl group
(--COOH), an ester group (--COOR, wherein R is one of a C.sub.1 to
C.sub.6 linear or branched alkyl group), a phenyl group, and a
phenyl group substituted with a C.sub.1 to C.sub.6 alkyl group,
in Chemical Formula 2-2,
Y is one of O, S, and NR (wherein R is selected from hydrogen, a
cyano group (CN), and a C.sub.1 to C.sub.6 linear or branched alkyl
group), and
in Chemical Formula 2-5,
R.sup.12 is one of hydrogen, a cyano group (CN), a carboxyl group
(--COOH) and an ester group (--COOR, wherein R is a C.sub.1 to
C.sub.6 linear or branched alkyl group), and
m is an integer of 0 to 1.
The n-type semiconductor compound represented by Chemical Formula 1
includes naphthalene diimide as a core, and a naphthyl group of the
core is fused with an S-containing ring (Cy1 and Cy2) and provides
the compound with a conjugation structure. The compound having this
conjugation structure may absorb light having a long wavelength
compared with naphthalene diimide including no S-containing
ring.
In addition, the S-containing ring has electron-withdrawing
properties, and may selectively absorb light in a green wavelength
region ranging from about 500 nm to about 600 nm.
In Chemical Formula 1, Cy1 and Cy2 may be the same or different.
When the Cy1 and Cy2 are different, the absorption wavelength range
may be minutely adjusted.
The n-type semiconductor compound represented by Chemical Formula 1
may have 6 to 10 rings, for example 6 to 8 rings. Herein, the rings
may indicate fused rings forming a conjugation structure. When the
number of the rings is greater than 10, the maximum absorption
wavelength of a compound moves toward red, and thus selective green
light absorption of the compound is deteriorated. In addition, when
the number of the rings is less than 6, the maximum absorption
wavelength of a compound moves toward blue, and thus, selective
green light absorption of the compound is deteriorated. In
addition, the green wavelength selectivity of the n-type
semiconductor compound may be improved by providing an appropriate
conjugation length.
In Chemical Formula 1, each of R.sup.1 and R.sup.2 may
independently be one of a substituted or unsubstituted C.sub.1 to
C.sub.6 linear or branched alkyl group, a substituted or
unsubstituted phenyl group, a substituted or unsubstituted
4-membered to 6-membered heteroaryl group, a substituted or
unsubstituted C.sub.3 to C.sub.6 cycloalkyl group, and a
substituted or unsubstituted 3-membered to 6-membered
heterocycloalkyl group, and thereby the n-type semiconductor
compound represented by Chemical Formula 1 may be desirably used
for a deposition process. For example, when a long alkyl group
(e.g., n-octyl or 2-hexyldecyl) is present in the R.sup.1 and
R.sup.2 as shown in Comparative Synthesis Examples 1 and 2, the
decomposition temperature of a compound becomes too high, and thus
a deposition process may not be performed. Accordingly, a
substituent of a substituted C.sub.1 to C.sub.6 linear or branched
alkyl group, a substituted phenyl group, a substituted 4-membered
to 6-membered heteroaryl group, a substituted C.sub.3 to C.sub.6
cycloalkyl group, and a substituted 3-membered to 6-membered
heterocycloalkyl group may be one of a halide group (--F, --Br,
--Cl, or --I), a hydroxy group, a nitro group, a cyano group, a
C.sub.1 to C.sub.4 alkyl group, a C.sub.2 to C.sub.4 alkenyl group,
a C.sub.2 to C.sub.4 alkynyl group, and a C.sub.1 to C.sub.4 alkoxy
group.
In addition, each of the R.sup.1 and R.sup.2 may independently be
one of a C.sub.1 to C.sub.6 linear or branched alkyl group
substituted with an electron withdrawing group, a phenyl group
substituted with an electron withdrawing group, a 4-membered to
6-membered heteroaryl group substituted with an electron
withdrawing group, a C.sub.3 to C.sub.6 cycloalkyl group
substituted with an electron withdrawing group, and a 3-membered to
6-membered heterocycloalkyl group substituted with an electron
withdrawing group. Herein, the electron-withdrawing group may be a
cyano group or a halide group.
The n-type semiconductor compound represented by Chemical Formula 1
may have a HOMO level ranging from about 5.8 to about 7.0 eV and a
LUMO level ranging from about 3.8 to about 5.0 eV. When the HOMO
and LUMO levels are respectively within the ranges, the
semiconductor compound may effectively absorb light in a green
wavelength region, and thus have high external quantum efficiency
(EQE), improving photoelectric conversion efficiency.
On the other hand, a method of forming a thin film may be formed in
a vacuum deposition method and a solution method. The vacuum
deposition method may include very few impurities in the film and
improve performance of a device. In addition, the solution method
has a problem in completely removing a solvent and a problem of
deteriorating a life-span or performance of a device due to
remaining solvent, which is not found in the vacuum deposition
method. Accordingly, the n-type semiconductor compound represented
by Chemical Formula 1 has a structure that is appropriate for a
vacuum deposition process as well as excellent selective light
absorption in a green wavelength region.
The n-type semiconductor compound represented by Chemical Formula 1
may have a molecular weight ranging from about 300 to about 900,
and specifically, about 350 to about 750. When the molecular weight
is within the range, the compound is effectively prevented or
inhibited from undergoing thermal decomposition as well as from
developing crystallinity during formation of a thin film in the
deposition method.
The n-type semiconductor compound represented by Chemical Formula 1
may have a decomposition temperature (Td) of greater than or equal
to about 250.degree. C., and specifically, greater than or equal to
about 300.degree. C. Herein, the decomposition temperature
indicates a temperature at which the weight of a compound starts to
decrease according to an exothermic reaction under an inert
atmosphere during thermogravimetric analysis. For example, the
decomposition temperature indicates a temperature at which the
weight of the compound is reduced by about 1% according to an
exothermic reaction when the temperature is increased at 10.degree.
C./min under the inert atmosphere during the thermogravimetric
analysis.
Accordingly, a compound having a molecular weight within the range
and the aforementioned decomposition temperature may adopt the
vacuum deposition method to manufacture a device and provide an
organic photoelectric device having excellent photoelectric
conversion performance.
The n-type semiconductor compound represented by Chemical Formula 1
may selectively absorb light in a green wavelength region, and thus
the active layer 30 including the compound may selectively absorb
light in a green wavelength region having a maximum absorption
wavelength (.lamda..sub.max) ranging from about 500 nm to about 600
nm, for example, about 520 nm to about 580 nm.
The active layer 30 may show a light absorption curve having a
relatively narrow full width at half maximum (FWHM) of about 50 nm
to about 140 nm. Herein, the FWHM is a width of a wavelength
corresponding to half of a maximum absorption point. As used
herein, when specific definition is not otherwise provided, it may
be defined by absorbance measured by UV-Vis spectroscopy. When the
full width at half maximum (FWHM) is within the range, selectivity
in a green wavelength region may be increased.
The active layer 30 further includes a p-type semiconductor
compound in order to form a pn junction with the n-type
semiconductor compound represented by Chemical Formula 1.
The p-type semiconductor compound may be a compound represented by
Chemical Formula 3.
##STR00007##
In Chemical Formula 3,
each of R.sup.21 to R.sup.23 are independently one of hydrogen, a
substituted or unsubstituted C.sub.1 to C.sub.30 alkyl group, a
substituted or unsubstituted C.sub.6 to C.sub.30 aryl group, a
substituted or unsubstituted C.sub.3 to C.sub.30 heteroaryl group,
a halide group, a halogen-containing group, and a combination
thereof,
each of a, b, and c are independently an integer ranging from 1 to
3, and
X is one of a halide group, for example, --F or --Cl, and
--Si(R.sup.a)(R.sup.b)(R.sup.c),
wherein each of the R.sup.a, R.sup.b, and R.sup.c are independently
one of a substituted or unsubstituted C.sub.1 to C.sub.30 alkyl
group, a substituted or unsubstituted C.sub.6 to C.sub.30 aryl
group, a substituted or unsubstituted C.sub.3 to C.sub.30
heterocyclic group, a substituted or unsubstituted C.sub.1 to
C.sub.30 alkoxy group, a substituted or unsubstituted amine group,
a substituted or unsubstituted C.sub.6 to C.sub.30 arylamine group,
a substituted or unsubstituted silyl group, and a combination
thereof.
In Chemical Formula 3, R.sup.21 to R.sup.23 may be electron
donating functional groups one of a substituted or unsubstituted
C.sub.1 to C.sub.30 alkyl group, a substituted or unsubstituted
C.sub.6 to C.sub.30 aryl group, and a substituted or unsubstituted
C.sub.3 to C.sub.30 heteroaryl group.
The p-type semiconductor compound may be a compound represented by
Chemical Formula 4.
##STR00008##
In Chemical Formula 4,
Z is one of Se, Te, S(.dbd.O), S(.dbd.O).sub.2, and
SiR.sup.aR.sup.b (wherein R.sup.a and R.sup.b are one of hydrogen
and a C.sub.1 to C.sub.10 alkyl group),
each of Ar.sup.1 and Ar.sup.2 are independently one of a
substituted or unsubstituted C.sub.6 to C.sub.30 aryl group and a
substituted or unsubstituted C.sub.4 to C.sub.30 heteroaryl
group,
each of R.sup.31 to R.sup.36 are independently one of hydrogen, a
substituted or unsubstituted C.sub.1 to C.sub.30 alkyl group, a
substituted or unsubstituted C.sub.6 to C.sub.30 aryl group, a
substituted or unsubstituted C.sub.4 to C.sub.30 heteroaryl group,
a halide, and a cyano group (CN),
m is an integer ranging from 0 to 4, and
n is 0 or 1.
The compound represented by Chemical Formula 4 may have 5 to 7
aromatic rings. Herein, the aromatic ring refers to a 5-membered or
6-membered ring that provides a ring conjugation structure.
Ar.sup.1 and Ar.sup.2 may be a substituted or unsubstituted C.sub.6
to C.sub.20 aryl group.
At least one of the Ar.sup.1 and Ar.sup.2 may be a naphthyl group
or an anthracenyl group.
At least one of the Ar.sup.1 and Ar.sup.2 may be one of a naphthyl
group and an anthracenyl group, and in example embodiments, one of
Ar.sup.1 and Ar.sup.2 may desirably be a naphthyl group. When at
least one of the Ar.sup.1 and Ar.sup.2 is a naphthyl group or an
anthracenyl group, aggregation among molecules in a film state may
be suppressed by reducing intermolecular interaction among the
molecules. Herein, absorption selectivity in a green wavelength may
be improved. When the Ar.sup.1 and Ar.sup.2 are not aromatic groups
but are alkyl groups or are fused each other and form an
N-containing cycloalkyl group, the compound has a planer structure
and an excessively wide full width at half maximum (FWHM) in a
light absorption curve.
The active layer 30 may be a single layer or a multilayer. The
active layer 30 may be, for example, an intrinsic layer (I layer),
a p-type layer/I layer, an I layer/n-type layer, a p-type layer/I
layer/n-type layer, a p-type layer/n-type layer, and the like.
The intrinsic layer (I layer) may include the n-type semiconductor
compound represented by Chemical Formula 1 and the p-type
semiconductor compound in a thickness ratio of about 1:100 to about
100:1. The compounds may be included in a thickness ratio ranging
from about 1:50 to about 50:1 within the range, for example, about
1:10 to about 10:1, and for another example, about 1:1. When the
compounds have a thickness ratio within the range, an exciton may
be effectively produced and a pn junction may be effectively
formed.
The n-type layer may include the n-type semiconductor compound
represented by Chemical Formula 1, and the p-type layer may include
the p-type semiconductor compound one of the semiconductor compound
represented by Chemical Formula 3, the semiconductor compound
represented by Chemical Formula 4, and a combination thereof.
The active layer 30 may have a thickness of about 1 nm to about 500
nm, for example, about 5 nm to about 300 nm. When the active layer
30 has a thickness within the range, the active layer may
effectively absorb light, effectively separate holes from
electrons, and deliver them, thereby effectively improving
photoelectronic conversion efficiency. An optimal thickness of a
thin film may be, for example, determined by an absorption
coefficient of the active layer 30, and may be, for example, a
thickness being capable of absorbing at least about 70% or more of
light, for example, about 80% or more of light, and for another
example, about 90% of light.
In the organic photoelectric device 100, when light enters from the
first electrode 10 and/or second electrode 20, and when the active
layer 30 absorbs light having a predetermined or given wavelength
region, excitons may be produced from the inside. The excitons are
separated into holes and electrons in the active layer 30, the
separated holes are transported to an anode that is one of the
first electrode 10 and the second electrode 20, and the separated
electrons are transported to the cathode that is the other of and
the first electrode 10 and the second electrode 20 so as to flow a
current in the organic photoelectric device.
Hereinafter, an organic photoelectric device according to example
embodiments is described with reference to FIG. 2.
FIG. 2 is a cross-sectional view showing an organic photoelectric
device according to example embodiments.
Referring to FIG. 2, an organic photoelectric device 200 according
to example embodiments includes a first electrode 10 and a second
electrode 20 facing each other, and an active layer 30 interposed
between the first electrode 10 and the second electrode 20, like
the example embodiments illustrated in FIG. 1.
However, the organic photoelectric device 200 according to example
embodiments further includes charge auxiliary layers 40 and 45
between the first electrode 10 and the active layer 30, and the
second electrode 20 and the active layer 30, unlike the example
embodiments illustrated in FIG. 1. The charge auxiliary layers 40
and 45 may facilitate the transfer of holes and electrons separated
from the active layer 30, so as to increase efficiency.
The charge auxiliary layers 40 and 45 may be at least one of a hole
injection layer (HIL) for facilitating hole injection, a hole
transport layer (HTL) for facilitating hole transport, an electron
blocking layer (EBL) for preventing or inhibiting electron
transport, an electron injection layer (EIL) for facilitating
electron injection, an electron transport layer (ETL) for
facilitating electron transport, and a hole blocking layer (HBL)
for preventing or inhibiting hole transport.
The charge auxiliary layers 40 and 45 may include, for example, an
organic material, an inorganic material, or an organic/inorganic
material. The organic material may be an organic compound having
hole or electron characteristics, and the inorganic material may
be, for example, a metal oxide (e.g., molybdenum oxide, tungsten
oxide, or nickel oxide).
The hole transport layer (HTL) may include one selected from, for
example, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)
(PEDOT:PSS), polyarylamine, poly(N-vinylcarbazole), polyaniline,
polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD),
4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (.alpha.-NPD),
m-MTDATA, 4,4',4''-tris(N-carbazolyl)-triphenylamine (TCTA), and a
combination thereof, but is not limited thereto.
The electron blocking layer (EBL) may include one selected from,
for example,
poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)
(PEDOT:PSS), polyarylamine, poly(N-vinylcarbazole), polyaniline,
polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD),
4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (.alpha.-NPD),
m-MTDATA, 4,4',4''-tris(N-carbazolyl)-triphenylamine (TCTA), and a
combination thereof, but is not limited thereto.
The electron transport layer (ETL) may include one selected from,
for example, 1,4,5,8-naphthalene-tetracarboxylic dianhydride
(NTCDA), bathocuproine (BCP), LiF, Alq.sub.3, Gaq.sub.3, Inq.sub.3,
Znq.sub.2, Zn(BTZ).sub.2, BeBq.sub.2, and a combination thereof,
but is not limited thereto.
The hole blocking layer (HBL) may include one selected from, for
example, 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA),
bathocuproine (BCP), LiF, Alq.sub.3, Gaq.sub.3, Inq.sub.3,
Znq.sub.2, Zn(BTZ).sub.2, BeBq.sub.2, and a combination thereof,
but is not limited thereto.
Either one of the charge auxiliary layers 40 and 45 may be
omitted.
The organic photoelectric device may be applied to various fields,
for example, a solar cell, an image sensor, a photo-detector, a
photo-sensor, and an organic light emitting diode (OLED), but is
not limited thereto.
Hereinafter, an example of an image sensor including the organic
photoelectric device is described referring to drawings. As an
example of an image sensor, an organic CMOS image sensor is
described.
FIG. 3 is a schematic view of an organic CMOS image sensor
according to example embodiments, and FIG. 4 is a cross-sectional
view of the organic CMOS image sensor of FIG. 3.
Referring to FIGS. 3 and 4, an organic CMOS image sensor 300
according to example embodiments includes a semiconductor substrate
310 integrated with photo-sensing devices 50B and 50R, a
transmission transistor (not shown), a charge storage 55, a lower
insulation layer 60, a color filter layer 70, an upper insulation
layer 80, and an organic photoelectric device 100.
The semiconductor substrate 310 may be a silicon substrate, and is
integrated with the photo-sensing devices 50B and 50R, the
transmission transistor (not shown), and the charge storage 55. The
photo-sensing devices 50B and 50R may be photodiodes.
The photo-sensing devices 50B and 50R, the transmission transistor,
and/or the charge storage 55 may be integrated in each pixel, and
as shown in the drawing, the photo-sensing devices 50B and 50R may
be respectively included in a blue pixel and a red pixel, and the
charge storage 55 may be included in a green pixel.
The photo-sensing devices 50B and 50R sense light, the information
sensed by the photo-sensing devices may be transferred by the
transmission transistor, the charge storage 55 is electrically
connected with the organic photoelectric device 100, and the
information of the charge storage 55 may be transferred by the
transmission transistor.
In the drawings, the photo-sensing devices 50B and 50R are, for
example, arranged in parallel without limitation, and the blue
photo-sensing device 50B and the red photo-sensing device 50R may
be stacked in a vertical direction.
A metal wire (not shown) and a pad (not shown) are formed on the
semiconductor substrate 310. In order to decrease signal delay, the
metal wire and pad may be made of a metal having low resistivity,
for example, aluminum (Al), copper (Cu), silver (Ag), and alloys
thereof, but are not limited thereto. Further, it is not limited to
the structure, and the metal wire and pad may be positioned under
the photo-sensing devices 50B and 50R.
The lower insulation layer 60 is formed on the metal wire and the
pad. The lower insulation layer 60 may be made of an inorganic
insulating material (e.g., a silicon oxide and/or a silicon
nitride), or a low dielectric constant (low K) material (e.g., SiC,
SiCOH, SiCO, and SiOF). The lower insulation layer 60 has a trench
exposing the charge storage device 55. The trench may be filled
with fillers.
The color filter layer 70 is formed on the lower insulation layer
60. The color filter layer 70 includes a blue filter 70B formed in
the blue pixel and a red filter 70R filled in the red pixel. In
example embodiments, a green filter is not included, but a green
filter may be further included.
The color filter layer 70 may be omitted. For example, when the
blue photo-sensing device 50B and the red photo-sensing device 50R
are stacked in a vertical direction, the blue photo-sensing device
50B and the red photo-sensing device 50R may selectively absorb
light in each wavelength region depending on their stack depth, and
the color filter layer 70 may not be equipped.
The upper insulation layer 80 is formed on the color filter layer
70. The upper insulation layer 80 eliminates a step caused by the
color filter layer 70 and smoothes the surface. The upper
insulation layer 80 and the lower insulation layer 60 may include a
contact hole (not shown) exposing a pad, and a through-hole 85
exposing the charge storage 55 of the green pixel.
The organic photoelectric device 100 is formed on the upper
insulation layer 80. The organic photoelectric device 100 includes
the first electrode 10, the active layer 30, and the second
electrode 20 as described above.
The first electrode 10 and the second electrode 20 may be
transparent electrodes, and the active layer 30 is the same as
described above. The active layer 30 selectively absorbs light in a
green wavelength region and replaces a color filter of a green
pixel.
When light enters from the second electrode 20, the light in a
green wavelength region may be mainly absorbed in the active layer
30 and photoelectronically converted, while the light in the rest
of the wavelength region passes through first electrode 10 and may
be sensed in the photo-sensing devices 50B and 50R.
An organic photoelectric device including the n-type semiconductor
compound represented by Chemical Formula 1 and the p-type
semiconductor compound shows excellent selective green absorption,
and thus may be usefully applied to an image sensor having a
stacking structure shown in FIGS. 3 and 4. As described above, the
organic photoelectric device selectively absorbing light in a green
wavelength region is stacked, and thereby a size of an image sensor
may be decreased and a down-sized image sensor may be realized.
In FIG. 4, the organic photoelectric device 100 of FIG. 1 is
included, but it is not limited thereto, and thus the organic
photoelectric device 200 of FIG. 2 may be applied in the same
manner. FIG. 5 shows a structure of an image sensor having such a
structure, and is a cross-sectional view of an organic CMOS image
sensor 400 including the organic photoelectric device 200 in FIG.
2.
FIG. 6 is a schematic cross-sectional view showing an organic CMOS
image sensor according to example embodiments.
Referring to FIG. 6, the organic CMOS image sensor 500 according to
example embodiments includes a semiconductor substrate 310
integrated with photo-sensing devices 50B and 50R, a transmission
transistor (not shown), a charge storage 55, an insulation layer
80, and an organic photoelectric device 100, like the example
embodiments illustrated in FIG. 5.
However, the organic CMOS image sensor 500 according to example
embodiments includes the blue photo-sensing device 50B and the red
photo-sensing device 50R that are stacked and does not include a
color filter layer 70, unlike the example embodiments illustrated
in FIG. 5. The blue photo-sensing device 50B and the red
photo-sensing device 50R are electrically connected with the charge
storage, and the information of the charge storage device 55 may be
transferred by the transmission transistor (not shown). The blue
photo-sensing device 50B and the red photo-sensing device 50R may
selectively absorb light in each wavelength region depending on a
stack depth.
An organic photoelectric device including the n-type semiconductor
compound represented by Chemical Formula 1 and the p-type
semiconductor compound shows excellent selective green light
absorption, and thus may be usefully applied to an image sensor
having a stacking structure shown in FIG. 6. As described above,
the organic photoelectric device selectively absorbing light in a
green wavelength region is stacked and the red photo-sensing device
and the blue photo-sensing device are stacked, and thereby a size
of an image sensor may be decreased and a down-sized image sensor
may be realized. As described above, the organic photoelectric
device 100 has improved green wavelength selectivity, and crosstalk
caused by unnecessary absorption of light in a wavelength region
except green may be decreased while increasing sensitivity.
In FIG. 6, the organic photoelectric device 100 of FIG. 1 is
included, but it is not limited thereto, and thus the organic
photoelectric device 200 of FIG. 2 may be applied in the same
manner.
FIG. 7 is a schematic view showing an organic CMOS image sensor
according to example embodiments.
Referring to FIG. 7, the organic CMOS image sensor 500 according to
example embodiments includes a green photoelectric device (G)
selectively absorbing light in a green wavelength region, a blue
photoelectric device (B) selectively absorbing light in a blue
wavelength region, and a red photoelectric device (R) selectively
absorbing light in a red wavelength region that are stacked.
In the drawing, the red photoelectric device (R), the blue
photoelectric device (B) and the green photoelectric device (G) are
sequentially stacked, but the stack order may be changed without
limitation.
The green photoelectric device (G) may be the above organic
photoelectric device 100, the blue photoelectric device (B) may
include electrodes facing each other and an active layer interposed
therebetween and including an organic material selectively
absorbing light in a blue wavelength region, and the red
photoelectric device (R) may include electrodes facing each other
and an active layer interposed therebetween and including an
organic material selectively absorbing light in a red wavelength
region.
As described above, the organic photoelectric device (G)
selectively absorbing light in a green wavelength region, the
organic photoelectric device (B) selectively absorbing light in a
blue wavelength region and the organic photoelectric device (R)
selectively absorbing light in a red wavelength region are stacked,
and thereby a size of an image sensor may be decreased and a
down-sized image sensor may be realized.
The image sensor may be applied to various electronic devices, for
example a mobile phone, a digital camera, and the like, but is not
limited thereto.
Hereinafter, the present disclosure is illustrated in more detail
with reference to examples. However, these are examples, and the
present disclosure is not limited thereto.
SYNTHESIS EXAMPLES
Synthesis Example 1
A compound including a functional group provided in Table 1 is
synthesized according to the following Reaction Scheme 1.
##STR00009## ##STR00010##
A compound 2 is synthesized according to a method provided in, J.
Org. Chem. 2007, 72, P. 8074. 1 g (1.7 mmol) of the compound 2 is
suspended in 17 ml of acetic acid, 6.8 mmol of n-hexylamine is
added thereto, and the mixture is heated at 120.degree. C. for 25
minutes. Then, the resultant is cooled down to 24.degree. C., and
130 ml of water is added thereto. The obtained precipitate is
cleaned with water, obtaining a compound 3. The compound 3 is
dissolved in 44 ml of dehydrated toluene, 30.66 ml (7.0 mmol) of
PBr is added thereto, and the mixture is heated and refluxed for 12
hours under an argon atmosphere. Then, the resultant is cooled down
to 24.degree. C., 50 ml of water is added thereto, and the mixture
is extracted with toluene. An organic layer obtained therefrom is
then purified through silica gel column chromatography (development
solvent: toluene:hexane=a volume ratio of 3:2), obtaining a
compound 4. 0.2 mmol of the compound 4 and 0.06 mmol of sodium
1,1-dicyanoethene-2,2-thiolate are dissolved in 30 ml of
tetrahydrofuran (THF), and the solution is heated and agitated at
50.degree. C. for 1 and a half hours. Then, a solid obtained by
taking a precipitate therefrom is cleaned in THF, obtaining 92 mg
of a compound represented by Chemical Formula 1a (yield: 55%).
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.17 (t, 4H), 1.75-1.73
(m, 4H), 1.39-1.37 (m, 12H), 0.92 (t, 6H)
Synthesis Example 2
A compound represented by Chemical Formula 1b (62 mg, yield: 55%)
is obtained according to the same method as Synthesis Example 1,
except for using methylamine instead of the n-hexylamine.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.01 (s, 6H)
##STR00011##
Synthesis Example 3
A compound (93 mg, yield: 67%) represented by Chemical Formula 1c
is obtained according to the same method as Synthesis Example 1,
except for using aniline instead of the n-hexylamine.
.sup.1H NMR (300 MHz, DMSO-d.sub.6) .delta. 7.50 (t, 4H), 7.41 (t,
2H), 7.33 (d, 4H)
##STR00012##
Synthesis Example 4
A compound represented by Chemical Formula 1d (85 mg, yield: 60%)
is obtained according to the same method as Synthesis Example 1,
except for using dimercaptomaleonitrile disodium instead of the
sodium 1,1-dicyanoethene-2,2-thiolate.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.18 (t, 4H), 1.75-1.73
(m, 4H), 1.39-1.38 (m, 12H), 0.92 (t, 6H)
##STR00013##
Synthesis Example 5
0.1 mmol of the compound represented by Chemical Formula 1a
according to Synthesis Example 4 is dissolved in 20 ml of propionic
acid, 0.8 ml of hydrogen peroxide is added thereto, and the mixture
is heated and agitated at 120.degree. C. for 3 hours. The resultant
is cooled down to 24.degree. C., and 20 ml of methanol is added
thereto, obtaining a solid compound represented by Chemical Formula
1e (46 mg, yield: 70%).
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.18 (t, 4H), 1.74-1.72
(m, 4H), 1.40-1.37 (m, 12H), 0.92 (t, 6H)
##STR00014##
Synthesis Example 6
A compound represented by Chemical Formula 1f (106 mg, yield: 68%)
is obtained according to the same method as Synthesis Example 1,
except for using 2-cyano-3,3-dimercapto-2-propenoic acid
methylester instead of the sodium
1,1-dicyanoethene-2,2-thiolate.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.17 (t, 4H), 3.81 (s,
4H), 1.75-1.73 (m, 4H), 1.38-1.37 (m, 12H), 0.91 (t, 6H)
##STR00015##
Synthesis Example 7
A compound represented by Chemical Formula 1g (82 mg, yield: 62%)
is obtained according to the same method as Synthesis Example 1,
except for using cyanoiminodithiocarbonic acid instead of the
sodium 1,1-dicyanoethene-2,2-thiolate.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.19 (t, 4H), 1.75-1.73
(m, 4H), 1.38-1.36 (m, 12H), 0.93 (t, 6H)
##STR00016##
Synthesis Example 8
A compound represented by Chemical Formula 1h (139 mg, yield: 98%)
is obtained according to the same method as Synthesis Example 1,
except for using 1,2-benzendithiol instead of the sodium
1,1-dicyanoethene-2,2-thiolate.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.37-7.35 (m, 4H),
7.21-7.19 (m, 4H), 4.18 (t, 4H), 1.75-1.73 (m, 4H), 1.39-1.38 (m,
12H), 0.92 (t, 6H)
##STR00017##
Synthesis Example 9
A compound represented by Chemical Formula 1i (50 mg, yield: 35%)
is obtained according to the same method as Synthesis Example 1,
except for using the sodium 1,1-dicyanoethene-2,2-thiolate in an
amount of 0.3 mmol instead of 0.6 mmol and 0.3 mmol of disodium
dimercaptomaleonitrile.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.18 (t, 4H), 1.73 (m,
4H), 1.38 (m, 12H), 0.92 (t, 6H)
##STR00018##
Synthesis Example 10
0.1 mmol of the compound represented by Chemical Formula 1i
according to Synthesis Example 9 is dissolved in 20 ml of propionic
acid, 0.8 ml of hydrogen peroxide is added thereto, and the mixture
is heated and agitated at 120.degree. C. for 3 hours. The resultant
is cooled down to 24.degree. C., and 20 ml of methanol is added
thereto, obtaining a solid compound represented by Chemical Formula
1j (50 mg, yield: 73%).
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.18 (t, 4H), 1.73 (m,
4H), 1.38 (m, 12H), 0.92 (t, 6H)
##STR00019##
Comparative Synthesis Example 1
A compound represented by Chemical Formula 1k (92 mg, yield: 60%)
is obtained according to the same method as Synthesis Example 1,
except for using n-octylamine instead of the n-hexylamine.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.30 (t, 4H), 1.80 (m,
4H), 1.25-1.30 (m, 20H), 0.86 (t, 6H)
##STR00020##
Comparative Synthesis Example 2
A compound represented by Chemical Formula 1l (106 mg, yield: 52%)
is obtained according to the same method as Synthesis Example 1,
except for using 2-hexyldecylamine instead of the n-hexylamine.
.sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.22 (d, 4H), 2.00 (m,
2H), 1.25 (m, 48H), 0.85-0.87 (m, 12H)
##STR00021## Deposition Temperatures of Compounds According to
Synthesis Examples 1 to 10 and Comparative Synthesis Examples 1 and
2
When each compound according to Synthesis Examples 1 to 10 and
Comparative Synthesis Examples 1 and 2 is deposited at a rate of 1
.ANG./s, a temperature of a crucible containing the compound is
measured and provided in the following Table 1.
TABLE-US-00001 TABLE 1 Deposition temperature (.degree. C.)
Synthesis Example 1 350 Synthesis Example 2 305 Synthesis Example 3
390 Synthesis Example 4 310 Synthesis Example 5 320 Synthesis
Example 6 335 Synthesis Example 7 345 Synthesis Example 8 360
Synthesis Example 9 345 Synthesis Example 10 355 Comparative
Synthesis Example 1 >450 (deposition is impossible) Comparative
Synthesis Example 2 >450 (deposition is impossible)
Deposition Temperatures and Light Absorption Characteristics of
Compounds According to Synthesis Examples 1 to 10 and Comparative
Synthesis Examples 1 and 2
Light absorption characteristics of the compounds in a solution
state and in a thin film state are measured.
The light absorption characteristics of the compounds according to
Synthesis Examples 1 to 10 and Comparative Synthesis Examples 1 and
2 in a solution state are measured by respectively dissolving them
in CH.sub.2Cl.sub.2 to have a concentration of 1.0.times.10.sup.-5
mol/L. The maximum absorption wavelength of the compounds in a
solution state is calculated by using a UV-2450 UV-Visible
Spectrophotometer (Shimadzu Co.).
Light absorption characteristics in a thin film are obtained by
thermally depositing each compound according to Synthesis Examples
1 to 10 and Comparative Synthesis Examples 1 and 2 and a p-type
semiconductor compound in a volume ratio of 1:1 under high vacuum
(<10.sup.-7 Torr) at a rate of 0.5-1.0 .ANG./s to respectively
form a 70 nm-thick thin film and measuring its maximum absorption
wavelength in a thin film with a UV-2450 UV-Visible
Spectrophotometer (Shimadzu Co.). The results are provided in Table
2.
The p-type semiconductor compound may include SubPcCl (a compound
represented by Chemical Formula 3, wherein R.sup.21 to R.sup.23 are
hydrogen, and X is Cl), a compound
(2-((5-(naphthalen-1-yl(phenyl)amino)selenophen-2-yl)methylene)-1H-indene-
-1,3(2H)-dione) represented by Chemical Formula 4-1, or a compound
represented by Chemical Formula 4-2.
##STR00022##
TABLE-US-00002 TABLE 2 Thin film state Solution Chemical Chemical
state SubPcCl Formula 4-1 Formula 4-2 .lamda..sub.max FWHM
.lamda..sub.max FWHM .lamda..sub.max FWHM .lamda..su- b.max FWHM
(nm) (nm) (nm) (nm) (nm) (nm) (nm) (nm) Synthesis 574 38 580 135
538 120 564 129 Example 1 Synthesis 572 35 578 133 535 117 565 130
Example 2 Synthesis 583 34 590 120 536 113 561 124 Example 3
Synthesis 547 98 585 130 540 125 567 133 Example 4 Synthesis 545 40
588 135 537 127 570 134 Example 5 Synthesis 581 34 586 132 541 130
572 136 Example 6 Synthesis 511 20 556 120 538 109 562 124 Example
7 Synthesis 584 85 587 132 539 125 565 128 Example 8 Synthesis 557
75 590 133 533 128 565 129 Example 9 Synthesis 543 83 583 128 537
133 567 130 Example 10
Referring to the results of Table 2, each compound according to
Synthesis Examples 1 to 10 in a thin film state respectively has a
maximum absorption wavelength (.lamda..sub.max) in a range of 500
nm to 600 nm and a full width at half maximum (FWHM) in a range of
83 nm to 140 nm, and thus shows excellent absorption regarding
light in a green wavelength region.
Manufacture of Organic Photoelectric Device
Example 1
An about 150 nm-thick anode is formed by sputtering ITO on a glass
substrate, and a 5 nm-thick charge auxiliary layer is formed
thereon by codepositing molybdenum oxide (MoO.sub.x,
0<x.ltoreq.3) and Al. Subsequently, a 70 nm-thick active layer
is formed on the molybdenum oxide (MoO.sub.x):Al thin film by
codepositing the compound according to Synthesis Example 1 (an
n-type semiconductor compound) and SubPcCl (a p-type semiconductor
compound) in a thickness ratio of 1:1. Subsequently, a 10 nm-thick
charge auxiliary layer is formed on the active layer by depositing
molybdenum oxide (MoO.sub.x, 0<x.ltoreq.3). A 7 nm-thick cathode
is formed on the charge auxiliary layer by sputtering ITO,
resultantly manufacturing an organic photoelectric device.
Examples 2 to 10
An organic photoelectric device is manufactured according to the
same method as Example 1, except for respectively using each
compound (an n-type semiconductor compound) according to Synthesis
Examples 2 to 10 instead of the compound (an n-type semiconductor
compound) according to Synthesis Example 1.
External Quantum Efficiency (EQE)
External quantum efficiency (EQE) of each organic photoelectric
device according to Examples 1 to 10 depending on a wavelength and
a voltage is evaluated.
The external quantum efficiency is measure by using an IPCE
measurement system (McScience Inc., Korea). Firstly, equipment is
calibrated by using a Si photodiode (Hamamatsu Photonics K.K.,
Japan) and mounted with each organic photoelectric device according
to Examples 1 to 10, and its external quantum efficiency is
measured in a wavelength region ranging about 300 to 700 nm.
FIG. 8 shows the external quantum efficiency (EQE) of the organic
photoelectric device according to Example 1 depending on a
wavelength.
Referring to FIG. 8, the organic photoelectric device according to
Example 1 shows satisfactory external quantum efficiency (EQE) in a
green wavelength region ranging from about 500 nm to 600 nm.
While this disclosure has been described in connection with what is
presently considered to be practical example embodiments, it is to
be understood that the invention is not limited to the disclosed
embodiments, but, on the contrary, is intended to cover various
modifications and equivalent arrangements included within the
spirit and scope of the appended claims.
* * * * *